At a state park, a grandfather and his family see a couple shape shift into murderous monsters and drive off. Inside the car sits the grandfather, his wife Alicia, their grandchildren Evie and Tom, his son Robert, and Jackie, Robert’s wife. The grandfather’s family has always experienced these changes among some members. Robert did not inherit the contagious monster ability and hates taking his family out because of it. Robert begs the grandfather to stop. The grandfather believes Robert was unhappy to have been born a mortal human. The family has been ostracized for generations since they were thought to be witches, demons, and more. Robert had taken the family to the state park on a rare occasion, as he usually keeps them at home. However, there is no way to predict the monster transformations or attacks.   The grandfather and Alicia are laid down upstairs in bed after the park. In the middle of the night, Alicia crawls under the bed several times. The grandfather feels sometimes it’s safer than lying close to her. The next morning, the grandfather looks outside and sees the children cornering a mail carrier by the garage. Alicia also appears there, naked and crawling on all fours. The grandfather laments that the mail carrier will die from a simple mistake of coming to the wrong address, but he also justifies his family when they act like this. For example, he says that Robert doesn’t understand that humans are animals, so Alicias's walking on all fours is acceptable.   The mail carrier begins to transform into a monster and the grandfather quickly heads outside. Robert comes out of the cellar holding an axe and heads toward the children. The grandfather shoves Robert away from the front door, and the axe falls on his chest, killing him. The grandfather then asks Evie and Tom to help him find Alicia in the woods. He sees her running around in a frenzy. He knows the person Alicia is now in her senility is “a broken spirit" so he heads back to the house with the kids. Later in the afternoon, Evie and Tom fight over who can keep a tree burl. They fight until they bleed everywhere, and the grandfather attempts to intervene but falls into a brush. The children approach him as he cries out in pain and agony, and kill him.